Friend of mine has a 311 cat believed to be a 1995. It's started skipping ,running rough with slight vibration most noticeably around 3/4 throttle! The problem occurred 2 or 3 times briefly before becoming now permeant ! He also feels that it has excessive pressure coming from the breather tube now! Not sure if it's all related . Any help would be great.. Thanks
Based on recent experience, check the engine mountings as a first step.
Thanks nige for the reply! Nearest we can tell the mounts look ok! Balancer and belts all look good also ! Is there any chance the coupler between the pump and motor could be giving us this issue?
I suggested the coupling on a recent problem of vibratio - it turned out to be the engine mounts.... I would check the mounts with the engine running and see what they do.
The mounts and coupling would account for vibration, but not skipping or excess crankcase pressure. What are the hours on the engine? When was the last service?
Around 4500 hours! Last serviced 100 hrs ago
Have you ruled out bad fuel or water in the fuel? I'm not familiar with that exact machine, but is the IP getting positive pressure at the inlet or is it pulling a vacuum?
I had a 315C that did the same thing at throttle setting 7 only, you never noticed it till the door was open and could hear it, I had cat tinker with it while under warranty ....... Needless to say they couldn't figure it out and the machine now has 4k on it and has done it since new, figure it out post back I am curious too Pj
Them there Mitsubishi based engined have a screen hidden in on of the fuel line fittings on the suction side. Has it been cleaned?
Stupid typos